What gear for 6K in 1/4 mile?

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Brad G

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3000# car with 340 +.030
10-1 comp. ratio
.500 lift cam with 230*@ .050
stock X heads
Air Gap with 750 Demon
904 with low 1st gear
2500 stall convertor
275-60-15 Drag Radial
What rearend gear to go thru the traps at 6K in 1/4 mile? Thanks, Brad.
 
I'd say either 4.30 or 4.10 depending on the diameter of the tire.
 
With a 28" tire (275/60), you may need more than 4.11.

Converter slip can make it tricky to figure too.

If you have some idea of what the car will mph, there is a good calculator here.

http://www.wallaceracing.com/calcmph.php

From your combo I am going to guess 105-110 mph with a good tune in the carb and timing figured out. This is a guess, so if that's lower than you think I mean no offense.

According to the calc, 28" tire, 4.10, 6000 RPM = 121 mph.

Same numbers a 4.30 gets 116 mph, 4.56 gets you 109 - all these get drug down by converter slip a little. Moper is probably right about the 4.30 with your combo.

As an alternative, you could go 4.11 (easier to find) and if that isn't enough, maybe go to a 26" tire?

Sounds like a fun combo. Good luck!
 
Why limit it to 6K? Safety or the ability to keep it together? That 500 lift cam may like higher RPM's...
 
I'm going to make guess that your car will run 105 mph in the 1/4 mile and et at 12.5.
With that you gear with 15 inch tire's you would need a 4.41 gear which they don't make so you would need a 4.30.
So rpm's would be 5825 and add a couple hundred rpm's for converter slip and you would get 6125 rpm's.
 
My Dart with a 26'' tall tire and 4.30's runs 6200 thru the lights.
 
Im running a '26 slick on my Dart and im running 4.10's.My motor is a 10 to 1 408 stroker with about the same cam you have.Mine is .484/.510 with 230 duration and its done at 6000 rpm.I run 11.40 flat in the 1/4 at 114 mph and go through the traps at 6200-6300 .I think my car would run a faster with 3.90 gears ,but havent tried it to confirm ...
 
My 360 with 230@50 .488 cam ran out of umph at about 5500 and best E/T was shifting at 5K. Changed from 4.30 to 3.91 and went from a 27.3" tire to a 29 and picked up about .4 when all was said and done! Car laid down at about 1000' with the 4.30's and pulled all the way through with the 3.91 and taller tire.
 
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